This study uses international survey data from more than 50 nations around the world to measure and analyze social differences in people's health as they have changed since the early 1980s. PUBLIC HEALTH RELEVANCE: Social scientists have devoted substantial attention to the relationship between income inequality and health, but results have been mixed, and studies have not examined cross-national variation in social inequalities in health. Social scientists have also devoted substantial attention to describing and explaining health disparities, but such studies rarely take a comparative approach. We address the limitations of both literatures, by testing hypotheses concerning the role of cross- national institutional differences in accounting for variation in health disparities across countries. Building on our previous research and existing studies that demonstrate the variability of socioeconomic gradients in health, we will use existing international survey data from the World Values Survey (five waves, 1981-2005) and the European Social Survey (four waves, 2002-2008) to place health disparities in a global comparative context. We will contribute to the debate over the income inequality hypothesis by testing the hypothesis that the level of and long-run change in income inequality in a society is associated with socioeconomic inequalities in health. We will also contribute to the comparative political economy of health by testing the hypotheses that labor market conditions, the health infrastructure, and the welfare state interact with individual- level characteristics in determining health outcomes.